Paola Borgiani

CYP4F2 genetic variant (rs2108622) significantly contributes to warfarin dosing variability in the Italian population

INTRODUCTION It is known that warfarin treatment is problematic, due to its narrow therapeutic range and to the great interindividual variability. Numerous papers have shown the important contribution of CYP2C9 and VKORC1 genetic variants to this variability. Recently, a new SNP within the CYP4F2 gene was found associated with warfarin dose in the USA. AIMS The aim of our work was to replicate this study in the Italian population and to assess the new CYP4F2 variant relative contribution in explaining warfarin dose variability with respect to CYP2C9 and VKORC1 genetic variants together with age and weight. MATERIALS & METHODS CYP4F2 rs2108622 genotyping was performed by allelic discrimination assay by TaqMan technology. Analysis of variance and multiple linear regression analyses were carried out to examine the contribution of genetic and nongenetic factors. RESULTS Our TT patients require 5.49 mg/day versus 2.93 mg/day of our CC patients. Analysis of variance indicates that about 7% of mean weekly warfarin dose variance is explained by CYP4F2 genotype. Our linear regression model including CYP4F2, CYP2C9 and VKORC1 genetic variants, age and weight, explains 60.5% of the interindividual variability. CONCLUSION Our data confirm and strengthen the role of this variant.

Association of single nucleotide polymorphisms in the oxidised LDL receptor 1 (OLR1) gene in patients with acute myocardial infarction

Acute myocardial infarction (AMI) is a significant cause of mortality and morbidity. Substantial data support a plausible role for oxidised LDL (oxLDL) in the aetiology of this disease.1,2 The human OLR1 (or LOX 1) gene encodes the endothelium derived lectin-like oxidised low density lipoprotein (oxLDL) receptor, which is involved in the binding, internalisation, and proteolytic degradation of oxLDL, suggesting that it may play a significant role in atherogenesis.3 OLR1 is considered a good candidate for atherosclerosis and AMI since it is induced in vitro by inflammatory cytokines and in vivo by pro-atherogenic conditions like hypertension, hyperlipidaemia, and diabetes mellitus.4 Recently, upregulation of OLR1 has been shown in ischaemia reperfusion injury in the rat.5 OLR1 acts as a mediator of “endothelial dysfunction” favouring superoxide generation, inhibiting nitric oxide production, and enhancing endothelial adhesiveness for monocytes.6–8 It is noteworthy that the versatile activities of OLR1 also include the ability to bind not only oxLDL, but also aged red blood cells, apoptotic cells, and activated platelets.4 With this background, we sought to validate the hypothesis of OLR1 involvement in atherosclerosis and AMI by defining OLR1 genetic variation by an association study of intragenic SNPs. ### Study subjects The study included 150 individuals with AMI who were referred to the Centre of Atherosclerosis at the Medical School of the Tor Vergata University of Rome. All cases were clinically evaluated and all underwent coronary angiography and left ventriculography. The diagnosis of AMI was based on typical electrocardiographic changes and increased serum activities of at least two enzymes, such as creatine kinase, aspartate aminotransferase, and lactate dehydrogenase. The diagnosis was confirmed by the presence of wall motion abnormality on left ventriculography and attendant stenosis (>50%) in any of the major coronary arteries or in the left main coronary artery on coronary …

Allelic variants in the CYP2C9 and VKORC1 loci and interindividual variability in the anticoagulant dose effect of warfarin in Italians.

INTRODUCTION Warfarin is currently considered to be the anticoagulant of choice in the long-term treatment and prevention of thromboembolic events. However, it presents a narrow therapeutic range and a great interindividual dose variability. We investigated the influence of variants of the VKORC1 and CYP2C9 loci on the mean weekly warfarin dose (MWWD) required to reach stabilized therapeutic international normalized ratio, in order to confirm and to estimate the contribution of common genetic variability of these two genes in an Italian population and to search for novel rare VKORC1 alleles. METHODS A total of 148 patients were followed for 6 months and analyzed for VKORC1 and CYP2C9 gene variants. Analysis of variance and multiple linear regression analysis were used to study the contribution of each genetic factor to MWWD requirement. RESULTS The complete sequencing of the VKORC1 coding region did not reveal the presence of exonic variants, while two common noncoding SNPs were highly associated: the T allele of VKORC1 1173C>T SNP (tag-SNP of H1-H2 haplotypes) is highly associated with low MWWD (p < 0.0001), while the A allele of VKORC1 3730G>A SNP (tag-SNP of H9 haplotype) is associated with high MWWD (p = 0.001). Also, CYP2C9*2 (Arg144Cys) and CYP2C9*3 (Ile359Leu) variant alleles were significantly associated with low MWWD (p = 0.003 and 0.027, respectively). According to a multiple linear regression model including, besides VKORC1 and CYP2C9 SNPs, also age and weight, this percentage reaches 56% (gender is not significant). DISCUSSION Our results clearly indicate VKORC1 as the gene with the largest contribution to MWWD. Analyzing only one tag SNP of VKORC1 gene (1173C>T), it is possible to foresee 20% of the total variability. Our results may contribute to give useful indications for clinicians especially in the initiation of therapy so as to avoid the risk of adverse events.

Nevirapine-induced hepatotoxicity and pharmacogenetics: a retrospective study in a population from Mozambique

AIMS Nevirapine is widely used to treat HIV-1 infection to prevent mother-to-child transmission; unfortunately adverse drug reactions have been reported. Our aim was to identify genes/variants involved in nevirapine-induced hepatotoxicity. MATERIALS & METHODS Patients from Mozambique, 78 with nevirapine-induced hepatotoxicity and 78 without adverse events, were genotyped for ABCB1, CYP2B6, CYP3A4 and CYP3A5 gene variants. We conducted a case-control association study and a genotype/phenotype correlation analysis. RESULTS The ABCB1 c.3435C>T SNP was associated with hepatotoxicity (p = 0.038), with the variant T allele showing a protective effect (odds ratio: 0.42). Moreover, four SNPs in the CYP2B6 and CYP3A5 genes resulted significantly correlated with transaminase values. In particular, for the CYP2B6 c.983T>C SNP, the difference in the alanine aminotransferase mean values were highly significant between TT and TC genotypes (p < 0.001). CONCLUSION Our preliminary results confirm the contribution of the ABCB1 c.3435C>T SNP in nevirapine-induced hepatotoxicity risk and, at the same time, suggest the necessity for further studies.

ACP1 and human adaptability. 1. Association with common diseases: a case-control study.

Human red cell acid phosphatase (ACP1) is a polymorphic enzyme closely related to cytosolic low molecular weight acid phosphatases, a protein family broadly conserved among eukaryotes. Two different functions have been proposed for ACP1: flavin mononucleotide (FMN) phosphatase and phosphotyrosine phosphatase (PTPase). Given that genetic variants of ACP1 activity are common, the enzyme could have a role in regulating a large spectrum of cellular functions and, in turn, disease susceptibility. In the present paper we report a study of ACP1 genetic polymorphism in 1088 normal subjects and in 1267 subjects from the population of Rome admitted to hospital for a number of common diseases. All ACP1 parameters investigated show highly significant differences among samples, suggesting that the enzyme may have a significant role in some of the diseases considered. In particular, consistent associations of ACP1 with developmental disturbances and with hemolytic favism have been observed. In the majority of diseases showing association with ACP1, only one of the two ACP1 isoforms, f and s, is involved, supporting the hypothesis of a functional differentiation between the two enzymatic fractions.

Both Maternal and Foetal Genetic Factors Contribute to Macrosomia of Diabetic Pregnancy

The study of 230 diabetic mothers along with their newborn babies has shown that foetal macrosomia is associated with two specific genomic sites: phosphoglucomutase locus 1 (PGM1)-Rhesus blood group (Rh) linkage group (chromosome 1) and HindIII restriction fragment length polymorphism (RFLP) linked to insulin-like growth factor 1 (IGF1) (chromosome 12). In PGM(1)2-1 mothers carrying the E allele, there is a proportion of 8.7% of macrosomic newborns as compared with 39.6% in mothers with other genotypes. The relationship between the maternal PGM1-RhE genotype and neonatal macrosomia does not depend on the type of diabetes. The proportion of macrosomic infants is much lower among newborns carrying the IGF1HS allele of the HindIII RFLP linked to IGF1 (20%) than among IGF1F/IGF1HF newborns (55%).

Impact of the CYP4F2 p.V433M polymorphism on coumarin dose requirement: systematic review and meta-analysis.

A systematic review and a meta‐analysis were performed to quantify the accumulated information from genetic association studies investigating the impact of the CYP4F2 rs2108622 (p.V433M) polymorphism on coumarin dose requirement. An additional aim was to explore the contribution of the CYP4F2 variant in comparison with, as well as after stratification for, the VKORC1 and CYP2C9 variants. Thirty studies involving 9,470 participants met prespecified inclusion criteria. As compared with CC‐homozygotes, T‐allele carriers required an 8.3% (95% confidence interval (CI): 5.6–11.1%; P < 0.0001) higher mean daily coumarin dose than CC homozygotes to reach a stable international normalized ratio (INR). There was no evidence of publication bias. Heterogeneity among studies was present (I2 = 43%). Our results show that the CYP4F2 p.V433M polymorphism is associated with interindividual variability in response to coumarin drugs, but with a low effect size that is confirmed to be lower than those contributed by VKORC1 and CYP2C9 polymorphisms.

CARD15 mutation analysis in an Italian population: Leu1007fsinsC but neither Arg702Trp nor Gly908Arg mutations are associated with Crohn's disease

BackgroundCARD15 gene mutations have been demonstrated to confer a high risk of Crohn’s disease (CD). Despite this, recent studies reported variable associations between CD and CARD15 mutations in distinct ethnic groups, thus raising the hypothesis that genetic and/or allelic heterogeneity may influence the relationship between CARD15 and CD. The purpose of this study was to evaluate the frequency of the main mutations of the CARD15 gene (Leu1007fsinsC, Arg702Trp, and Gly908Arg) in Italian CD patients and to establish possible genotype-phenotype correlations. MethodsOne hundred sixty-five CD patients and 125 healthy subjects were consecutively enrolled from January to November 2001. The Leu1007fsinsC mutation was assessed by denaturing high-performance liquid chromatography and Arg702Trp and Gly908Arg mutations by Pyrosequencing technology. ResultsAmong the CARD15 gene mutations tested, only the Leu1007fsinsC was associated with CD (30/165 CD patients, 18%, versus 3/125 healthy subjects, 2.4%; p < 0.001). In particular, 23 CD patients were heterozygotes and 7 were homozygotes. No healthy subject exhibited the mutant homozygous genotype. Odds ratios for CD were 6.9 for heterozygotes and 41.0 for homozygotes. The genotype-phenotype analysis revealed that a fibrostenosing CD of the distal ileum was more frequent in patients carrying the Leu1007fsinsC mutation. ConclusionsThis study confirms the association between CARD15 gene mutations and CD and shows that only the Leu1007fsinsC mutation is a risk factor of CD in an Italian population.

IL-4 receptor alpha chain genetic polymorphism and total IgE levels in the English population: two-locus haplotypes are more informative than individual SNPs.

The IL‐4RA locus encodes for the alpha chain of the IL‐4 receptor, and is both a functional and positional candidate gene for atopy and allergic disease. Recently Ober et al. have shown that the study of haplotypes at multiple loci in the IL‐4RA gene could be more informative than the separate study of single nucleotide polymorphisms (SNPs).

TRAF3IP2 gene is associated with cutaneous extraintestinal manifestations in Inflammatory Bowel Disease

BACKGROUND AND AIMS Genome-wide association (GWA) studies recently identified a novel gene, TRAF3IP2, involved in the susceptibility to psoriasis. Common immune-mediated mechanisms involving the skin or the gut have been suggested. We therefore aimed to assess the role of TRAF3IP2 gene in IBD, with particular regard to the development of cutaneous extraintestinal manifestations (pyoderma gangrenosum, erythema nodosum). The association with psoriasis was also assessed in a secondary analysis. METHODS The analysis included 267 Crohns disease (CD), 200 ulcerative colitis (UC) patients and 278 healthy controls. Three TRAF3IP2 SNPs were genotyped by allelic discrimination assays. A case/control association study and a genotype/phenotype correlation analysis have been performed. RESULTS All three SNPs conferred a high risk to develop cutaneous manifestations in IBD. A higher risk of pyoderma gangrenosum and erythema nodosum was observed in CD patients carrying the Rs33980500 variant (OR 3.03; P=0.026). In UC, a significantly increased risk was observed for both the Rs13190932 and the Rs13196377 SNPs (OR 5.05; P=0.02 and OR 4.1; P=0.049). Moreover, association of TRAF3IP2 variants with ileal (OR=1.92), fibrostricturing (OR=1.91) and perianal CD (OR=2.03) was observed. CONCLUSIONS This is the first preliminary report indicating that TRAF3IP2 variants increase the risk of cutaneous extraintestinal manifestations in IBD suggesting that the analysis of the TRAF3IP2 variants may be useful for identifying IBD patients at risk to develop these manifestations.